day 14...

src/main/kotlin/de/linkel/aoc/Day14.kt

@@ -2,13 +2,127 @@ package de.linkel.aoc
 
 import de.linkel.aoc.base.AbstractLinesAdventDay
 import de.linkel.aoc.base.QuizPart
+import de.linkel.aoc.utils.grid.Area
+import de.linkel.aoc.utils.grid.Grid
+import de.linkel.aoc.utils.grid.Point
+import de.linkel.aoc.utils.grid.Vector
 import jakarta.inject.Singleton
+import kotlin.math.abs
 
 @Singleton
 class Day14: AbstractLinesAdventDay<Int>() {
     override val day = 14
 
     override fun process(part: QuizPart, lines: Sequence<String>): Int {
-       return 0
+        val grid = Grid.parse(lines) { pos, char ->
+            char.takeIf { it != '.' }
+        }
+        var platform = Platform(
+            width = grid.width,
+            height = grid.height,
+            rollers = grid.getAllData()
+                .filter { it.data == 'O' }
+                .map { it.point }
+                .toSet(),
+            blockers = grid.getAllData()
+                .filter { it.data == '#' }
+                .map { it.point }
+                .toSet()
+        )
+        if (part == QuizPart.A) {
+            platform = platform.tilt(Platform.NORTH)
+        } else {
+            val lastIterations = mutableListOf<Int>()
+            var i = 0
+            while (i < 1_000_000_000) {
+                platform = platform
+                    .tilt(Platform.NORTH)
+                    .tilt(Platform.WEST)
+                    .tilt(Platform.SOUTH)
+                    .tilt(Platform.EAST)
+                if (platform.rollers.hashCode() in lastIterations) {
+                    val cycleLength = lastIterations.indexOf(platform.rollers.hashCode()) + 1
+                    println("in lastIterations at pos $cycleLength")
+                    while (i + cycleLength < 1_000_000_000) {
+                        i += cycleLength
+                    }
+                    println(" > fast-forward to iteration $i")
+
+                    lastIterations.clear()
+                }
+                lastIterations.add(0, platform.rollers.hashCode())
+                if (lastIterations.size > 500) {
+                    lastIterations.removeAt(500)
+                }
+                i++
+            }
+        }
+        return platform.rollers
+            .sumOf { platform.height - it.y }
+    }
+
+    data class Platform(
+        val width: Int,
+        val height: Int,
+        val rollers: Set<Point>,
+        val blockers: Set<Point>
+    ) {
+        companion object {
+            val NORTH = Vector(0, -1)
+            val WEST = Vector(-1, 0)
+            val SOUTH = Vector(0, 1)
+            val EAST = Vector(1, 0)
+        }
+
+        val area = Area(0, 0, width, height)
+
+        fun tilt(direction: Vector): Platform {
+            val points = rollers
+                .toMutableSet()
+            val stoppedRollers = mutableSetOf<Point>()
+
+            val (edge, selector) = when (direction) {
+                NORTH -> 0 to { it: Point -> it.y }
+                SOUTH -> height to { it: Point -> it.y }
+                WEST -> 0 to { it: Point -> it.x }
+                EAST -> width to { it: Point -> it.x }
+                else -> throw Exception("invalid direction")
+            }
+            while (points.isNotEmpty()) {
+                points.toList()
+                    .sortedBy { abs(edge - selector(it)) }
+                    .forEach { pos ->
+                        val dest = pos + direction
+                        points.remove(pos)
+                        if (dest in area && dest !in blockers && dest !in stoppedRollers && dest !in points) {
+                            points.add(dest)
+                        } else {
+                            stoppedRollers.add(pos)
+                        }
+                    }
+            }
+            return copy(
+                rollers = stoppedRollers
+            )
+        }
+
+        override fun toString(): String {
+            return buildString {
+                (0 until height).forEach { y ->
+                    (0 until width).forEach { x ->
+                        val p = Point(x, y)
+                        if (p in blockers) {
+                            append('#')
+                        } else if (p in rollers) {
+                            append('O')
+                        } else {
+                            append('.')
+                        }
+                    }
+                    append('\n')
+                }
+            }
+        }
     }
+
 }

src/main/kotlin/de/linkel/aoc/Day15.kt

@@ -0,0 +1,14 @@
+package de.linkel.aoc
+
+import de.linkel.aoc.base.AbstractLinesAdventDay
+import de.linkel.aoc.base.QuizPart
+import jakarta.inject.Singleton
+
+@Singleton
+class Day15: AbstractLinesAdventDay<Int>() {
+    override val day = 15
+
+    override fun process(part: QuizPart, lines: Sequence<String>): Int {
+       return 0
+    }
+}

src/main/kotlin/de/linkel/aoc/Day16.kt

@@ -0,0 +1,14 @@
+package de.linkel.aoc
+
+import de.linkel.aoc.base.AbstractLinesAdventDay
+import de.linkel.aoc.base.QuizPart
+import jakarta.inject.Singleton
+
+@Singleton
+class Day16: AbstractLinesAdventDay<Int>() {
+    override val day = 16
+
+    override fun process(part: QuizPart, lines: Sequence<String>): Int {
+       return 0
+    }
+}

src/test/kotlin/de/linkel/aoc/Day14Test.kt

@@ -2,12 +2,22 @@ package de.linkel.aoc
 
 class Day14Test: AbstractDayTest<Int>() {
     override val exampleA = """
+O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....
         """.trimIndent()
-    override val exampleSolutionA = 0
-    override val solutionA = 0
+    override val exampleSolutionA = 136
+    override val solutionA = 108889
 
-    override val exampleSolutionB = 0
-    override val solutionB = 0
+    override val exampleSolutionB = 64
+    override val solutionB = 104671
 
     override val implementation = Day14()
 }

src/test/kotlin/de/linkel/aoc/Day15Test.kt

@@ -0,0 +1,13 @@
+package de.linkel.aoc
+
+class Day15Test: AbstractDayTest<Int>() {
+    override val exampleA = """
+        """.trimIndent()
+    override val exampleSolutionA = 0
+    override val solutionA = 0
+
+    override val exampleSolutionB = 0
+    override val solutionB = 0
+
+    override val implementation = Day15()
+}

src/test/kotlin/de/linkel/aoc/Day16Test.kt

@@ -0,0 +1,13 @@
+package de.linkel.aoc
+
+class Day16Test: AbstractDayTest<Int>() {
+    override val exampleA = """
+        """.trimIndent()
+    override val exampleSolutionA = 0
+    override val solutionA = 0
+
+    override val exampleSolutionB = 0
+    override val solutionB = 0
+
+    override val implementation = Day16()
+}